Walla Walla County, WA Accessory Structures: ADU Rental Restrictions (2026)

WWCC 17.08.015(K) states plainly that an accessory dwelling unit may be rented, the provision that lets a Walla Walla County property owner draw rental income from a garage apartment, basement unit, or detached cottage in the unincorporated county. The permission comes with conditions attached elsewhere in the same section. Condition L requires one additional off-street parking space for the ADU on top of what a single-family dwelling already needs. Conditions M and N confine ADUs to lots that already carry a one-family dwelling, meaning a rented ADU can never become a stand-alone second household on a lot without a primary house.

Condition O adds a use-mixing restriction inside urban growth areas: an ADU cannot share a lot with a licensed family day care or a home occupation, so an owner renting out an ADU in the Walla Walla or College Place urban growth areas cannot also run a home business or in-home daycare on that same parcel. The rental permission in K works together with the owner-occupancy rule in condition J: because the owner cannot collect rent on the unit they personally occupy, condition K is really what authorizes renting the other unit, whichever one that is. Community Development reviews these conditions when it issues the building permit for a new ADU and can revisit compliance later through code enforcement.